Allow activity in ActivityEmbedding split to get Task windowing mode

Before, when we are in ActivityEmbedding split, the TaskFragment
windowing mode is always set the WINDOWING_MODE_MULTI_WINDOW, which
overrides the activity windowing mode, and it causes the app process
unaware of the Task windowing mode. Now, when the Task is multi
windowing mode, we set the TaskFragment windowing mode to the same as
the Task.

Bug: 230446204
Test: atest WMJetpackUnitTests:JetpackTaskFragmentOrganizerTest
Test: atest WMJetpackUnitTests:TaskContainerTest
Change-Id: Id78a86359297c0c225043b14844441445711f89d